Method of identifying leaks in vacuum-sealed bipolar secondary battery

Abstract

To provide method of identifying leaks in a vacuum-sealed bipolar secondary battery, which allows for grasping the condition of leakage of vacuum-sealed batteries.SOLUTION: A method of identifying leaks in a pressure-sealed bipolar secondary battery is provided, the method comprising: setting a battery module 11 on a jig 12 for supporting or gripping edges of the battery module 11 with a reduced pressure; measuring the amount of deflection of the battery module 11 using a displacement meter; and determining whether the battery module 11 is leaking or not on the basis of a correlation between a known internal pressure of the battery module and the amount of deflection.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for detecting leakage in a vacuum sealed bipolar secondary battery. [Background technology]

[0002] Patent Document 1 describes a method of inspecting for He leakage by sealing He inside a can-type battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-183027 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with vacuum-sealed batteries, there are problems in that it is not possible to inject gas for leak testing into the battery, and it is also impossible to directly measure the internal pressure. [Means for solving the problem]

[0005] In one embodiment, a method for determining whether a battery module has leaked from a vacuum sealed bipolar secondary battery measures the amount of deflection of the battery module under reduced pressure, and determines whether the battery module has leaked from the correlation between the known internal pressure of the battery module and the amount of deflection. [Effects of the Invention]

[0006] According to the method for determining leakage in a vacuum sealed bipolar secondary battery of the present disclosure, the leakage state of a vacuum sealed battery can be determined. [Brief explanation of the drawings]

[0007] [Figure 1] 1A and 1B are perspective and cross-sectional views for explaining a method for determining leakage of a vacuum sealed bipolar secondary battery according to an embodiment of the present invention; [Figure 2] 1A and 1B are a top view and a cross-sectional view for explaining a method for determining leakage of a vacuum sealed bipolar secondary battery according to an embodiment of the present invention. [Figure 3] 10 is a graph showing the correlation between the internal pressure of a battery module and the amount of deflection. DETAILED DESCRIPTION OF THE INVENTION

[0008] This embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a perspective view and a cross section for explaining a method for detecting leakage in a vacuum sealed bipolar secondary battery according to this embodiment. The method for detecting leakage in a vacuum sealed bipolar secondary battery will be explained using Fig. 1.

[0009] As shown in the upper part of Fig. 1, the battery module 11 is set on a jig 12 that supports or grips the end of the battery module 11 in a depressurized state. The depressurized battery module 11 is, for example, a bipolar battery whose interior has been depressurized and sealed in a depressurized state. The jig 12 that supports / grapples the end is, for example, a square-shaped pallet with a square opening in the center, or a hand that grips only the end.

[0010] 1, a displacement meter is used to measure the amount of deflection of the battery module 11. Then, based on the correlation between the known internal pressure of the battery module and the amount of deflection, it is determined whether or not there is a leak in the battery module 11.

[0011] Next, the correlation between the internal pressure of the battery module and the amount of deflection will be explained. Tests were conducted on a bipolar battery module with a variable internal pressure and no electrolyte. Figure 2 shows a top view and a cross-sectional view for explaining the method for determining leakage of a vacuum sealed bipolar secondary battery according to this embodiment. 1. Place the battery module 11 on a flat table, adjust the pressure in all cells evenly to 10 kPa, and then seal the pressure adjusting valve. 2. Place the module on a 30mm square aluminum frame (jig 12) assembled in a U-shape. Each side should rest on the aluminum frame by approximately 20mm. The side of the liquid inlet should not be supported. 3. While monitoring the internal pressure value with a pressure gauge, open the pressure regulating valve to adjust the internal pressure to the appropriate level. The deflection amount at the center of the module is measured at each internal pressure (measured at two locations: the electrode and the groove). To measure the deflection amount, a virtual reference 21 is set from the floor, and the displacement is measured using a scale. 4. The amount of deflection is the difference when the initial state is 10 kPa. The pressure is calculated using the actual measured value indicated by the pressure gauge.

[0012] The internal pressure test standards are shown in Table 1. [Table 1]

[0013] The test results are shown in Figure 3, which is a graph showing the correlation between the internal pressure of the battery module and the amount of deflection. As shown in Figure 3, there is a correlation between the internal pressure of the battery module and the amount of deflection, and since the amount of deflection increases as the pressure is restored, it is possible to determine whether there is a leak.

[0014] As described above, according to the method for determining leakage from a vacuum sealed bipolar secondary battery of this embodiment, the rigidity of the entire battery changes depending on the reduced pressure / vacuum state inside the bipolar battery, and the leakage state of the battery can be determined by measuring the amount of deformation due to its own weight while supporting the end of the battery.

[0015] The present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the present invention. For example, the present invention may be applied to a bipolar battery having a series structure in which positive and negative electrode foils are laminated. [Explanation of symbols]

[0016] 11 Battery module 12 Jig

Claims

[Claim 1] Setting the battery module on a jig that supports or grips the end of the battery module in a decompressed state; measuring the amount of deflection of the battery module using a displacement meter; determining whether or not there is a leak in the battery module based on a known correlation between the internal pressure of the battery module and the amount of deflection; A method for detecting leaks in vacuum sealed bipolar secondary batteries.

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